Portable stage



April 11, 1951 K. H. wlLsoN 2,978,754

PORTABLE STAGE INVENTOR. KERM/ r HWVLsoN .AT TORNE YS April l1, 1961 K.H. wlLsoN PORTABLE STAGE 6 Sheets-Sheet 2 Filed Nov. 16, 1959 INVENTOR.

KERM/T H WLsoN if WM ATTO/:PNE YS April 11, 1961 K.' H. wlLsoN 2,978,754

PORTABLE STAGE Filed Nov. 16, 1959 6 Sheets-Sheet 3 INVENTOR. KERM/T H.XIV/sow A TTOPNEYS April ll, 1961 K. H. wlLsoN 2,978,754

PORTABLE STAGE Filed Nov. 16, 1959 6 Sheets-Sheet 4 INV ENTOR.

Kanu/T H. W/Lso/v BY MM/f April 11, 1961 K. H. WILSON 2,978,754

PORTABLE STAGE Filed Nov. 16, 1959 6 Sheets-Sheet 5 INVENTOR. KERM/r HWl/ soN AT TORNEYS April ll, 1961 Filed NOV. 16, 1959 K. H. WILSONPORTABLE STAGE 6 Sheets-Sheet 6 .lll

.KERM/T l. VWLsoN ATTORNEYS nited States PORTABLE STAGE Kermit H.Wilson, 7a Sico Mfg. C0., 5212 Eden Ave. S., Minneapolis, Minn.

Filed Nov. 16, 1959, Ser. No, $53,323

17 Claims. (Cl. 2011.123)

My invention relates generally to portable stages or platformstructures, and more particularly to such structures which are adaptedto be folded or otherwise arranged, when not in use, for easytransportation and storage.

An important object of my invention is the provision of a device asherein described, which may bey quickly and easily set up for operationby a single person, and as quickly and easily folded and moved to asuitable place of storage.

Another object of my invention is the provision of a device as set forthwhich, when folded, occupies a minimum of ground or oor area.

Another object of my invention is the provision of a device as setforth, having a supporting frame, ground engaging wheels on said framefor movements toward and away from the ground, a flat top elementmovable between operative and storage positions on said frame, andconnections between the top element and said wheels whereby, when thetop element is moved to an operative horizontal position, the wheels areraised out of engagement with the oor or ground to cause the top elementto be supported by the frame, and whereby, when the top element is movedto its storage position, the wheels are lowered into engagement with theground, and the frame is raised out of its engagement with the ground.

Another object of my invention is the provision of structure as setforth comprising a at top element, a frame pivotally supporting one endportion of said top element for swinging movements between ahorizontally disposed operative position and a generally verticallydisposed storage position, supporting means at the opposite end portionof the top element, and connections between said frame and supportingmeans for automatically moving said supporting means between anoperative top element supporting position generally normal to the topelement and a folded storage position generally parallel with the topelement responsive to movements of said top element between itsoperative and storage positions respectively.

Another object of my invention is the provision of a platform structureor the like including a pair of flat top elements normally horizontallydisposed in substantiallyr end to end relationship, a supporting frameunderlying the adjoining end portions of said top elements and pivotallymounting said to-p elements for independent swinging movements betweensaid normally horizontal positions and generally vertically disposedstorage positions overlying said frame, and of means at the outer endsof 'said top elements for detachably anchoring other like structuresthereto in end to end abutting relation.

Another object of my invention is the provision of folding structure ofthe type set forth having a plurality of top elements normallyhorizontally disposed in staired arrangement and supported at one end bya frame, and of means whereby said top elements may be movedsimultaneously to a generally vertically disposed storage positionoverlying said frame, said top elements in their stor- 2,978,754Patented Apr. 11, 1961v 2 age positions lying in a common generallyvertically disposed plane.

Still another object of my invention is the provision of a foldingstructure as set forth which is relatively inexpensive to produce, whichis light in weight and easily manipulated, and which is strong inconstruction and durable in use. The above, and still further highlyimportant objects and advantages of my invention will become apparentfrom the following detailed specification, appended claims and attacheddrawings.

Referring to the drawings, which illustrate the invention, and in whichlike reference characters indicate like parts throughout the severalviews:

Fig. 1 is a view in side elevation of a preferred form of the inventiondisposed in its operative position, some parts being broken away;

Fig. 2 is a view corresponding to Fig. 1, but showing a differentposition of the parts, some parts being broken away and some parts beingshown in section;

Fig. 3 is a view in end elevation of the device as positioned in Fig. 2,some parts being broken away and some parts being shown in section;

Fig. 4 is a fragmentary View in longitudinal section of the device aspositioned in Fig. l; Y

Fig. 5 is a transverse section taken substantially on the line 5 5 ofFig. l;

Fig. 6 is an enlarged fragmentary detail ycorresponding to a portion ofFig. 4, but showing a diierent position of some of the parts;

Fig. 7 is a view corresponding to Fig. 1, but showing a modified form ofthe invention;

Fig. 8 is a View in end elevation of the structure of Fig. 7;

Fig. 9 is a transverse section'taken substantially on the line 9 9 ofFig. 7; and

Fig. l0 is a view corresponding to Fig. 3, of the modilied form of theinvention illustrated in Figs. 7-9.

In the form of the invention illustrated in Figs. 1-6 inclusive, thenumeral 1 indicates in its entirety, a normally horizontally disposedflat top comprising cooperating flat top elements or sections 2 and 3.The elements or sections 2 and 3 are preferably rectangular in outline,and are preferably made from rigid plywood, wood planks, or any suitablematerial. The top elements 2 and 3 are bolted or otherwise rigidlysecured to generally rectangular brace frames 4 and 5 respectively,prefera'oly made from conventional angle iron and defining dependingmarginal flanges 6 and 7 respectively. The brace frames 4 and S furthercomprise cross brace members 8 and 9 which underlie their respective topelements 2 and 3 in spaced relation to the inner ends 2a and 3urespectively of the top elements 2 and 3.

The at top elements 2. and 3 are pivotally supported at their inner endportions 2a and 3a respectively by a' central supporting frame 1l)comprising pairs of vertically` disposed legs 11 and 12, and 13 and 14,the legs 11 and 12 being connected by a rigidY cross frame member l15;.

and the legs 13 and 14 being rigidly connected by a similar cross framemember 16. Vertically disposed rigidA arms 17 and 18 extend upwardly inspaced parallel relationship from the cross frame member 15,intermediate right arms 21 and 22 extend upwardly from the cross framemember 16 in spaced parallel relationship interme` diate the legs 13 and114, and are pivotally connected to;

the inner end portions of respective top elements 2 and 3, as indicatedat 23 and 24 respectively. The pivotall connections 19 and 23 are on acommon horizontal axis extending transversely of the top 1, and thepivotal con-ff' 3 nections 2t! and 24 are on a common horizontal axisparallel to the axis of the pivotal connections 19 and 23, whereby thetop elements 2 and 3 may be swung between their normally horizontalpositions shown in Figs. 1 and 4, and generally vertically disposedstorage positions shown in Figs. 2 and 3. rthe several memberscomprising the frame are preferably made from tubular steel or the like,the upper ends of the legs 1li-14 being provided with caps 25 whichengage adjacent portions of the brace frames 4 and 5, when the topelements 2 and Y 3 are in their operative horizontally disposedpositions, to

aid in supporting the top sections; and diametrically enlarged feet 26are applied to the lower ends of the several legs 11-14 to preventmarring or scratching of the ground or oor upon which the frame 1Grests, the floor being indicated by the reference character X.

The outer ends of the top elements 2 and 3 are supported by respectiveleg structures 27 and 28, each of the leg structures comprising a pairof laterally spaced legs 29 and 30 connected by rigid cross bars 31.Like the frame 10, the leg structures 27 and 28 are preferably made fromtubular metal, the legs 29 and 3i) thereof being provided with ground oriloor engaging feet 32 similar to the feet 26. The upper ends of thelegs 29 and 30 of each leg structure 27 and 28 are pivotally connectedto the outer end portions of respective top elements 2 and 3 asindicated at 33 and 34 respectively, see particularly Fig. 3, on alignedhorizontal axes parallel to the axis of the pivotal connections at theinner ends of the top elements 2 and 3. Cooperating control arms 35 and36 are pivotally connected at their inner ends to the legs 11 and 13respectively, as indicated at 37, on aligned horizontal axes parallel tothe axis of the pivotal connections 22 and 23. At their outer ends, thecontrol arms 35 and 36 are pivotally connected to the legs 29 and 30 ofthe leg structure 27, as indicated at 38, on aligned horizontal axesparallel to the aligned axes of the pivotal connections 33 and 34 of theleg structure 27. As shown par- 4 rticularly in Fig. l, when the topelement 2 is in its horizontally disposed operative position, the legs29 and 30 of the leg structure 27 are disposed substantially at rightangles to the plane of the top element 2. When the top element 2 isswung upwardly to its storage position of Fig. 2, the control arms 35and 36 cause the legs 29 and 30 of the leg structure 27 to swinginwardly toward generally parallel relationship with the top element 2,engagement of the feet 26 of the leg structure 27 with the adjacentportions of the marginal brace frame 4 limiting swinging movement of thetop element 2 beyond its storage position of Fig. 2. In the same manner,the legs 29 and 30 of the leg structure 28 are connected to respectivelegs 13 and 14 ofthe supporting frame 1t) by control arms 39 and 40pivotally connected at their inner ends to the legs 12 and 14, asindicated at 41, and at their outer ends to the legs 29 and 30 of theleg structure 28, as indicated at 42. The control arms 39 and 40 operatein the same manner as the control arms and 36 to move the leg structure28 into engagement of the feet 32 thereof with adjacent portions of themarginal frame 5 when the top element 3 is moved to its generallyvertically disposed storage position of Fig. 2. It will be noted, thatwhen the top elements 2 and 3 are in their folded storage positions ofFig. 2, that the upper ends of the arms 35, 36, 39 and 40 are disposedbeyond a dead center relationship between the axis of the pivotalconnections of the inner ends thereof and the axes of pivotal connectionof their respective legs 29 and 30 to the outer end portions of the topelements 2 and 3. This arrangement prevents accidental movement of thetop elements from their generally vertically disposed storage positionstoward their operative positions, it being necessary that the outer legstructures 27 and 28 or their respective control arms 35 and 36 or 39and 4t) be manually swung outwardly through said dead centerrelationship before the top elements 2 or 3 may be moved to theirhorizontally disposed operative positions.

With reference to Pigs. land 4, it will be seen that the inner ends 2aand 3a of the top elements 2 and 3 respectively are spaced apart whenthe top elements are in their horizontally disposed positions. For thepurpose of spanning the gap between the adjacent inner ends 2a and 3a, lprovide a rigid bridge element 43 which closely overlies the adjacentends 2a and 3a and which is supported by rigid legs or supporting bars44 welded or otherwise rigidly secured to the cross frame members 15 and16. The spacing between the pivot axes of the top-elements 2 and 3, andthe relationship between these pivot axes and the top surfaces of theirrespective top elements 2 and 3 is such that ample clearance is providedfor the bridge element 43 between the top elements when the same aremoved to their storage positions of Fig. 2.

For the purpose of lending mobility to the instant device, when the topelements 2 and 3 are in their folded or storage positions, whereby thestructure may be easily moved to a desired location, I provide novelmeans now to be described. A pair of elongated rigid mounting members orbars 45 and 46 are provided at their opposite ends with verticallydisposed tubular heads 47 and 48 respectively, and have mountedintermediate their ends pairs of caster wheels 49 and 50 respectively.The heads 47 of the mounting member 45 each slidably encompass one ofthe legs 11 and 13, the heads 48 of the mounting member 46 each slidablyencompassing one of the legs 12 and 14 of the frame structure 10, forgenerally vertical movements relative thereto. A pair of rigid links 51are pivotally connected at their lower ends to the mounting member orbar 45, as indicated at 52, and at their upper ends to brackets 53, asindicated at 54, The brackets 53 are welded or otherwise rigidly securedto the cross brace 8, the axes of the' pivotal connections 54 beingaligned, and in spaced parallel relation to the axis of pivotal movementof the top element 2. A similar pair of rigid links 55 are pivotallysecured at their lower ends on aligned horizontal axesto the wheelmounting member or bar l46, as indicated at 56, the upper ends of thelinks 55 being pivotally secured to brackets 57 on aligned horizontalaxes, and as indicated at S8. The brackets 57 are similar to thebrackets 53 and are welded or otherwise rigidly secured to the crossbrace 9 of the top element 3. The axis of the pivotal connections 58 isdisposed in spaced parallel relation to the axis of swinging or pivotalmovement of the top element 3, and the axis of the pivotal connections56 is parallel to both these axes.

The lengths of the rigid links 51 and 55 are such that, when the topelements 2 and 3 are disposed in their normal horizontal positions ofFig. 1, that the Wheels 49 and 50 are upwardly spaced from the ground orfloor X, the legs 11-14 of the supporting frame 10 and the legs 29 and30 of the leg structures 27 `and 28 engaging the oor'or ground X andcarrying the weight of the top elements 2 and 3. When it is desired tofold the structure for movement to a place of storage, the outer ends ofthe top elements 2 and 3 are individually raised to their generallyvertically disposed storage positions of Fig. 2. During upward swingingmovement of either of the top elements 2 or 3, for example the topelement 3, as shown in Fig. 6 and by dotted lines in Fig. 4, the pivotalconnections 58 move in an arc about the axis of the pivotal connections24 to cause downward movement of the wheel mounting member or bar 46,the legs 12 and 14 of the supporting frams 10 acting as guide membersfor the wheel mounting member 46. As the top element 3 approaches itsfolded or storage position, as indicated by dotted lines in Fig. 4, thewheels 50 make contact with the ground or floor X. Continuedswingingmovement ofthe top element 3 in the same direction causes the legs 12and 14 to be raised from engagement anveres with the floor X, the a-Xisof the pivotal connections 58 moving slightly beyond a dead centerrelationship between the axis of the pivotal connections 56 and 24. Withreference to Fig. 6, it will be noted that, when the top element 3 ismoved to its generally vertically disposed storage position, thesupporting frame becomes tilted, the same being supported at one side bythe wheels 50 and at its opposite side by the legs 11 and 13. Then, whenthe top element 2 is pivotally swung to its generally verticallydisposed storage position, the wheels 49 move into engagement with theground or floor X, and the legs 11 and 13 are raised out of engagementwith the floor, so that the entire structure is disposed as shown inFig. 2. In view of the fact that all of the pivotal connections betweenthe various parts of the above-described structure are on parallel axes,it is not necessary that the top elements 2 and 3 be moved between theiroperative and storage positions simultaneously but that the same may beso moved in succession by a single person. This novel arrangementfurther eliminates any binding between the frame legs 11-14 and theirrespective sliding heads 47 and 48 when the supporting frame 1t) istilted as shown in Fig. 6 during movement of one of the top elementsrelative to the other thereof.

'For the purpose of combining two or more structures as above describedto provide a stage or platform of considerable area, I provide aplurality of upwardly opening hooks 59. One each of the hooks 59 iswelded or otherwise rigidly anchored to each of the depending flanges 6and 7 at a common side of the top 1, and one hook 59 is likewise weldedto the marginal flange 7 at the outer end of the top element 3. Thebottoms of the hooks 59 are disposed at or below the level of the loweredges of the anges 6 and 7, the hooks 59 being adapted to receive thedepending marginal flanges of other like structures as indicated bydotted lines in Fig. l, the structures being adapted to be placed in endto end or in side by side relationship, `or both. The structures beingrelatively light in weight, it is an easy matter to manually raise oneside or end of the structure to place the marginal ange thereof into thecooperating hooks 59 of an adjacent one of the structures to anchoradjacent structures against relative sideways or endways movement.

The over dead center relationship of the upper ends of the control arms35, 36, 39 and 40 as well as that of the upper ends of the links 51 and55, when the top elements 2 and 3 are in their storage positions,contributes to the stability of the top elements in these positions andinsures against accidental movement of the top elements to theirhorizontally disposed positions during movement of the structure overrough places. It will be appreciated that, while the instant structurehas been described as a stage or platform, the lengths of the variouslegs 11-14, 29 and 3i) may be such that the structures may be used asfolding tables. Hence, the instant invention is intended to apply totables as well as platforms or stages, the forms shown herein beingillustrative of two examples thereof.

The form of the instant invention illustrated in Figs. 7-10 is commonlyknown in the trade as a choral riser, upon which persons may sit orstand at different levels, so that all thereon may be seen and heardwith equal clarity by an audience. This modification comprises a seriesof elongated platforms in side by side staired arrangement, the frontand lowermost platform being indicated generally by the numeral 60, theintermediate platform being indicated by the numeral 61 and disposedimmediately behind the lowermost platform 60, and the uppermost platformbeing indicated generally by the numeral 62 and disposed immediatelyrearwardly of the intermediate platform 61. The lowermost or frontplatform 60. comprises a pair of elongated platform elements 63 and 64,the intermediate platform comprising a similar pair of platform elements65 and 66, and the uppermost Si or rear platform 62 including a pair4 ofsimilar platform elements 67 and 68, the cooperating platform elementsof each of said platforms being normally horizontally disposed in end toend relationship, see Fig. 7. At their inner ends, the several platformelements are pivotally connected to a frame structure, indicatedgenerally at 69, the frame structure 69 comprising a plurality of rigidframe sections 70, 71, 72 and 73. The frame section 70 comprises a pairof vertical legs 74 and 75, a horizontally disposed bar 76 rigidlyconnecting the legs 74 and 75, and a pair of upright members 77 and 78to the upper ends of which are pivotally secured the inner end portionsof the platform elements 63 and 64, as indicated at 79. The framesection 71 comprises a pair yof vertical legs 80 and 81 and a rigidconnecting cross bar 82, the legs 86 and 81 being spaced apart adistance equal to the spacing between the upright members 77 and 78, theinner end portions of the intermediate platform elements 65 and 66 beingpivotally secured to the upper ends of respective legs 80 and 81 onhorizontal axes parallel to and vertically spaced from the axes of thepivotal connections 79, as indicated at 83. With reference to Figs. 9and l0, it will be seen that the inner end portions of the lowermostfront platform elements 63 and 64 are also pivotally connected torespective ones of the legs 80 and 81, as indicated at 84, on axesaligned with the yaxes of the pivotal connections 79. The frame section72 comprises a pair of vertically extending legs 85 and 86 spaced aparta distance equal to the spacing between the legs 80 and 81 of the framesection '71, and rigidly connected by a rigid cross bar 87, the innerend portions of the uppermost rear platform elements 67 and 68 beingpivotally connected to the upper ends of respective legs and 86, asindicated at 88 on horizontal axes parallel F to and upwardly spacedfrom the axes of pivotal movement of the platform elements of theintermediate and front platforms 61 and 60 respectively. With referenceto Figs. 9 and l0, it will be seen that the inner end portions of theintermediate platform elements 65 and 66 are pivotally connected to thelegs 85 and 86 respectively, as indicated at 89, on aligned aXes withrespective ones of the pivotal connections 83. The rearmost framesection 73 comprises a pair of vertically extending legs 90 and 91rigidly connected by a cross member 92 in spaced relation equal to thespacing of the legs 74 and 75. The frame section 73 further includes apair of upright members 93 and 94, see Figs. 9 and l0, that are spacedapart a distance equal to the spacing between the legs 85 and 86, theinner end portions of the platform elements 67 and 68 being pivotallyconnected to respective ones of the upright members 93 and 94, asindicated at 95, on horizontal axes aligned with-the axes of respectiveones of the pivotal connections 88.

With reference to Fig. 7, it will be seen that the adjacent inner endsof the cooperating elements comprising the several platforms 60, 61 4and62 are disposed in closely spaced relationship, when the platformelements are in their normally horizontally disposed operativepositions. In order to cover the spaces between the respective platformelements of each platform, I provide horizontally disposed flat toppedbridge elements 96, 97 and 98 for the platforms 60, 61 and 62respectively. The front end of the bridge element 96 is supported fromthe cross bar 76 by a rigid leg 99, the front end of the bridge element97 being supported by a rigid leg 100 extending upwardly from the crossmember S2, and the front and rear ends respectively of the bridgeelement 93 being supported by legs 101 and 102 extending upwardly fromthe cross bars 87 and 92 respectively. The rear end of the bridgeelement 96 is welded or otherwise rigidly secured to the leg 100,whereas the rear end of the bridge element 97 is Iwelded or otherwiserigidly secured to the leg 101, the several bridge elements 96, 97 and98, together with their respective supporting legs rigidly tying theseveral frame sections 70-73 together.

'1"he platform elements 63, 65 and 67 are supported at their outerv endportionsin their normally horizontally disposed operative positions by aleg structure 103, and the platform elements 64, 66 and 68 are similarlysupported by a corresponding leg structure 104. Each of the legstructures 103 and 104 comprises a plurality of outer legs 105, 106 and107, the upper ends of the legs 105 being pivotally connected to theadjacent end portions of their respective platform elements 65, asindicated at 108, for pivotal movements relative -to their respectiveplatform elements on horizontal axes parallel to the axes of the pivotalconnections at the inner ends of the platform elements. The outer endsof the platform elements 63 and 64 are likewise pivotally secured toadjacent legs 105, as indicated at 109, see Figs. 8 and l0. The outerends of the platform sections 65 and 66 are pivotally connected to theintermediate portions of adjacent legs 106 of their respective legstructures 103 and 104, as indicated at 110, on horizontal axes alignedwith the axes of their respective pivotal connections 108. The outerends of each of the platform elements 67 and 68 are pivotally connectedto the upper ends of the legs 106 and 107 of their respective legstructure 103 and 104, on aligned axes as indicated at 111. The legs 105and 106 of each of the leg structure 103 and 104 are rigidly connectedby cross members 112, and the legs 106 and 107 are similarly connectedby cross members 113. The outer ends of the lowermost or front platformelements 63 and 64 are further supported by relatively short legs 114that are rigidly secured to the outer 'end portions of their respectiveplatform elements 63 and 64.

It will be noted that the pivotal connections between the outer ends ofthe groups of platform sections and their respective leg structures 103and 104 are in Vertically spaced relationship like the relationshipbetween the pivotal connections of the inner ends thereof to the framestructure 69, all of these pivotal connections being parallel. With thisarrangement, the platform elements 63, 65 and 67 may be swung upwardlyabout the axes of their pivotal connections 79, 83 and 88 respectivelyto a generally vertically disposed storage position wherein the severalplatform elements 63, 65 and 67 are disposed in a common plane, asindicated by dotted lines in Fig. 7. The platform elements 64, 66 and 68may be likewise swung upwardly to a similar storage position,independently of the group of platform elements 63, 65 and 67. It willbe further noted that, when the several platform sections are moved totheir storage positions, their respective leg structures 103 and 104move between positions generally normal to the planes of theirrespective platform sections and inoperative folded positions generallyparallel to their respective platform elements. The legs 114, beingrelatively short, there is no necessity for pivotally connecting thesame to their respective platform elements 63 and 64, inasmuch as thelegs 114 project outwardly from the platform elements but a shortdistance when said platform elements are in their storage positions.

A pair of elongated mounting members 115 and 116 are provided at theiropposite ends with vertically extending tubular heads 117 and 118respectively, the heads 1117 each slidably encompassing a different oneof the legs 74 and 90 of the frame structure 69, the heads 118 eachllikewise slidably encompassing a different one of the legs 75 and 91.Intermediate their ends, the mounting members 115 and 116 are providedwith spaced groundengaging caster Wheels 119 and 120 respectively.Adjacent their front ends, the mounting members 115 and l116 areprovided with depending rigid iingers 121 to the lower ends of which arepivotally secured the opposite ends of a connector bar 122. A rigid link123 is pivotally connected at its lower end to the connector bar 122 inclosely spaced relationship to the pivotal connectionvof the connectorbar 122 with the depending nger 1.21 'of the 8. mounting member 115, theupper end of the link 123 being pivotally connected toa bracket 124rigidly secured to the inner end portion of the platform Velement 63. Arigid link 125, similar to the 4link 123, ispivotallyv connected to theconnector bar l122 closely adjacent the linger 121 of the mountingmember 116, and to a bracket 126 rigidly secured to the inner endportion of the platform section 64. Other rigid links 127 and 123 arepivotally secured at their lower ends to the rear end portions of themounting members and 116 respectively, and at their upper ends tobrackets 129 and 130 rigidly secured to the inner end portions of theplatform elements A67 and 68 respectively. The several links 123, 125,127 and 128 operate to lower the mounting members 115 and 116 intoengagement of their respective wheels 119 and 120 with the floor orground, and raise the `frame structure 69 out of engagement with theground, when the several platform elements are pivotally swung to theirdotted line storage positions of Fig. 7; and to raise the wheels out ofengagement with the door or ground and lower the frame structure 69 intoplatform supporting engagement with the floor or ground when the severalplatform elements are moved to their horizontally disposed operativepositions indicated by full lines in Fig. 7. This operation is identicalto that above described with respect to the form of the deviceillustrated in Figs. 1 6. With the above arrangement, raising of one ofthe staired groups, for example, the group comprising the platformelements 64, 66 and 68, causes the rigid link 125 to exert downwardpressure on the adjacent end portion of the connector bar 122, theconnector bar 122 swinging downwardly on the axis of its pivotalconnection to the opposite iinger 121 depending from the mounting member115. In other Words, the connector bar 122 functions as a lever totransfer downward movement of the link to the adjacent end portion ofits respective mounting member 116. Obviously, lowering of the platformelements 64, 66 and 68 will cause the connector bar 122 to swingupwardly on the above mentioned axis. Moving the opposite group ofplatform elements 63, 65 and 67, either upwardly or downwardly, willcause the connector bar 122 to swing in a corresponding direction aboutthe axis of its pivotal connection to the iinger 121 depending from theopposite mounting member 116, whereby to lower or raise the adjacent endof the mounting member 115.

Preferably, the platform elements of one staired group thereof, such asthe platform elements 64, 66 and 68, may be provided with upwardlyopening hooks 131 at the outer ends thereof whereby another choral risermay be releasably anchored to the one above described in the same manneras hereinbefore disclosed in connection with the form of the inventionillustrated in Figs. 1-6.

While I 'have shown and described two embodiments or forms which myinvention may take in actual practice, it will be understood that thesame is capable of vfurther modification, without departure from thespirit and scope of the invention as defined in the claims.

What I claim is:

1. In a device of the kind described, a normally horizontally disposedgenerally dat top element, a supporting frame for one end portion ofsaid top element, supporting means for the opposite end portion of saidtop element, means pivotally connecting said one end portion of the topelement to said frame `for swinging movements of said top elementbetween its normally horizontal position and a generally verticallydisposed storage positionand on a horizontal axis generally parallel tothe adjacent end of said top element, a plurality of wheels, wheelcarrying means mounted on said frame for movements toward and away fromsupporting engagement of said wheels with the ground, and linkageoperatively connected to said top element and the wheel carrying meansand responsive to movement of said top element to its normallyhorizontal position to move said wheel carrying means upwardly wherebysaid supporting frame 'rests upon 'the gr ground, said linkage beingresponsive to movement of said top element to said storage position tolower said Wheel carrying means into engagement of said wheels with theground and elevate said frame from engagement with the ground.

2. In a device of the kind described, a normally horizontally disposedgenerally at top element, a supporting frame for one end portion of saidtop element, leg structure pivotally connected to the opposite endportion of said top element for swinging movements between a top elementsupporting position generally normal to said top element and a storageposition generally parallel to said top element, means pivotallyconnecting said one end portion of the top element to said frame Iforswinging movements between its normally horizontal position and agenerally vertically disposed storage position and on a horizontal axisgenerally parallel to the adjacent end of said top element, a pluralityof wheels, wheel carrying means mounted on said frame yfor movementstoward and away from supporting engagement of said wheels with theground, and linkage operatively connected to said top element `and theWheel carrying means and responsive to movement of said top element toits normally horizontal position to move said wheel carrying meansupwardly `whereby said supporting frame rests upon the ground, saidlinkage being responsive to movement of said top element to said storageposition to lower said wheel carrying means into engagement of saidwheels with the ground and elevate said frame from engagement with theground.

3. The structure defined in claim 2 in which the axis of pivotalmovement of said leg structure is parallel to the axis of swingingmovement of said top element, and in further combination with a rigidcontrol arm pivotally secured to said frame and said leg structure forautomatically moving said leg structure between its operative andstorage positions during movement of said top element toward itsnormally horizontal and vertically disposed storage positionsrespectively.

4. In a device of the kind described, a normally horizontally disposedgenerally flat top element, a supporting frame for one end portion ofsaid top element, supporting means for the opposite end portion `of saidtop element, said frame defining spaced parallel generally verticalguide members, means pivotally connecting said one end portion of thetop element to said frame for swinging movements of said top elementbetween its normally horizontal position and a generally verticallydisposed storage position and on a horizontal axis generally parallel tothe adjacent end of said top element, a plurality of wheels, wheelcarrying means mounted lon said guide members for movements toward andaway from engagement of said wheels with the ground, a rigid linkpivotally secured at one end to said wheel carrying means and at itsother end to said top element' on axes parallel to the axis of swingingmovement of said top element, the axis of the pivotal connection betweensaid link and said top element being generally downwardly spaced fromthe axis of swinging movement of said top element, said link beingresponsive to movement of said top element to its normally horizontalposition to move said wheel carrying means upwardly relative to saidframe whereby said frame rests upon the ground, said linkage beingresponsive to movement of said top element to said storage position tolower said wheel carrying means into engagement of said wheels with theground and elevate said frame from engagement with the ground, and meanslimiting said swinging movement of said top element beyond said storageposition.

'5. The structure defined in claim 4 in which said frame includes vasupport portion engaging said top element in its lnormally horizontalposition to support said top element intermediate the pivotd connectingmeans of said top element and said supporting means.

6. lIn a device of the kind described, a top comprising tween theirnormally horizontal positions and generallyV vertically disposed storagepositions and on horizontal axes parallel to said inner ends of the topelements, a plurality of wheels, a pair of wheel carrying members oneeach underlying a different one of said top elements when in theirhorizontal positions and each mounted on said frame structure forindependent movements toward and away from engagement of the Wheels withthe ground, linkage operatively connected to said top elements and tounderlying ones of said wheel carrying members and responsive tomovement of the respective top elements to their normally horizontalpositions t'o move their respective wheel carrying members upwardlywhereby the frame structure rests upon the ground, said linkage beingresponsive to movement of said top elements to said storage positions tolower ther respective wheel carrying members into engagement of thewheels thereof with the ground and elevate said frame from engagementwith the ground, and means limiting said swinging movement of said topelement beyond said storage position.

7. The structure dened in claim 6 in which said supporting framestructure includes pairs of generally vertically extending legs, thelegs of each pair thereof being spaced apart longitudinally of saiddevice, each pair thereof being spaced apart transversely of saiddevice, said wheel carrying members each comprising an elongated barextending transversely of said device and each slidably mounted at itsopposite ends on one of the legs of each pair thereof.

8. The structure dened in claim 6 in which said supporting means for theouter ends of said top elements comprises la pair of independent legstructures each pivotally connected to the outer end portion of adifferent one of said top elements for swinging movements between a topelement supporting position generally normal to its respective topelement' and a storage position generally parallel to its respective topelements, the axes of swinging movements of said leg structures beinghorizontal and parallel to the axis of swinging movement of said topelements on said frame, said last mentioned means comprising rigidcontrol arms pivotally secured to said frame and said leg structures andautomatically moving said leg structures between their operativepositions and their storage positions during movement of said topelements toward their normally horizontal and vertically disposedstorage positions respectively.

9. In a device of the kind described, a normally horizontally disposedflat top element, a supporting frame for one end portion of said topelement, supporting means for the opposite end portion of said topelement', said opposite end of the top element defining a dependingflange, means pivotally connecting said one end portion of the topelement to said frame for swinging movements of said top element betweenits normally horizontal position and a generally vertically disposedstorage position and on a horizontal axis generally parallel to theadjacent end of said top element, a plurality of wheels, wheel-carryingmeans mounted on said frame for movements toward and away fromsupporting engagement of said wheels with the ground, linkageoperatively connected to said top element and the wheel carrying meansand responsive to movement of said top element to its normallyhorizontal position to move said wheel-carrying means upwardly wherebysaid supporting frame rests upon the ground, said linkage beingresponsive to movement of said top element to said storage position tolower said wheel-carrying means into engagement .of said wheels with theground and elevate said frame from engagement with the ground, meansvgevaren 11 limiting said swinging movement of said top element beyondsaid storage position, and an upwardly opening hook element on saiddepending ange, the bottom of said hook element being downwardly spacedfrom the top surface of the top element at least as far as the loweredge of said flange, said hook element being adapted to receive theflange of a second top element placed in end to end abutting relation tosaid inst-mentioned top element, whereby to anchor said top elementsagainst relative longitudinal displacement.

l0. in a device of the kind described, a top comprising a pair ofnormally horizontally disposed ilat top elements having spaced parallelinner ends, a supporting frame structure underlying the adjacent innerends of said top elements, supporting means for the outer end portionsof said top elements, means pivotally connecting the inner end portionsof said top elements to said frame structure for independent swingingmovements of said top elements between their normally horizontalpositions and generally vertically disposed storage positions and onhorizontal axes parallel to said inner ends of the top elements andspaced from the inner ends of their respective top elements in thedirection of the outer ends thereof, a plurality of wheels, a pair ofwheel-carrying members one each underlying a different one of said topelements when in their horizontal positions and each mounted on saidframe structure for independent movements toward and away fromengagement of the wheels with the ground, linkage operatively connectedto said top elements and to underlying ones of said wheel-carryingmembers and responsive to movement of their respective top elements totheir normally horizontal positions to move their respectivewheel-carrying members upwardly whereby the frame structure rests uponthe ground, said linkage being responsive to movement of said topelements to said storage positions to lower their respectivewheel-carrying members into engagement of the wheels thereof with theground and elevate said frame from engagement with the ground, meanslimiting said swinging movement of said top elements beyond said storagepositions thereof, and a bridge element mounted on said f-rame structureand spanning the space between the inner ends of said top elementssubstantially at the level of the top surface of said top elements whensaid top elements are disposed in their horizontal positions. 1l. Thestructure dened in claim l0 in which said bridge element is disposedimmediately above the plane of the top surfaces of said top elements,said bridge element having a width greater than that of the spacebetween said top elements in their horizontal positions, whereby tooverlap said adjacent end portions of the top elements.

l2. In a device of the kind described, a normally horizontally disposedgenerally flat top element, a supporting frame for one end portion ofsaid top element, supporting means for the opposite end portion of saidtop element, means pivotally connecting said one end portion of the topelement to said frame for swinging movements of said top element betweenits normally horizontal position and a generally vertically disposedstorage position and on a horizontal axis generally parallel to theadjacent end of said top element, a plurality of wheels, wheel carryingmeans mounted on said frame for movements toward and away fromsupporting engagement of said wheels with the ground, a rigid linkpivotally secured at one end to said wheel-carrying means and at itsother end to said top element on axes parallel to the axes of swingingmovement of said top element, the axis of the pivotal connection betweensaid link and said top element being generally downwardly spaced fromthe axis of swinging movement of said top element, said link beingresponsive to movement of said top element to its normally horizontalposition to move said wheel carrying means upwardly relative to saidframe whereby said frame rests upon the ground, said link beingresponsive to` movement of said top element to said storage position tolower Said wheel carrying means into engagement of said wheels with theground and elevate said frame from engagement with the ground, and acontrol arm pivotally connected to said supporting frame and saidsupporting -means to limit said pivotal movement of said top element inthe direction of said sto-rage position, said other end of the linkbeing disposed at one side of dead center relationship between the pivotaxis of swinging movement of said top element and the axis of pivotalconnection of said link to said wheel-carrying means when the topelement is moved to said storage position, said other end of the linkmoving to the other side of said dead center relationship during initialmovement of said top element toward its horizontal position.

13. 1n a device of the kind described, a plurality of elongated atplatform elements, a supporting frame, means for pivotally mounting saidplatform elements at one end to said supporting frame on generallyvertically spaced horizontal axes substantially parallel to the adjacentends of said platform elements for movements between parallelhorizontally disposed operative positions in staired arrangement andgenerally vertically disposed inoperative storage positions overlyingsaid frame, a support pivotally connected to the other end of each ofsaid platform elements on generally vertically spaced horizontal axesparallel to the pivot axes at said one end, whereby said platformelements partake of simultaneous movement between said operativepositions and said storage positions, a plurality of wheels, wheelcarrying means mounted on said frame for movements toward and away fromengagement of said wheels with the ground, and linkage operativelyconnected to one of said platform elements and to said wheel-carryingmeans and responsive to movement of said platform elements to theiroperative horizontal positions to move said wheel carrying meansupwardly whereby said supporting frame rests upon the ground, saidlinkage being responsive to movement of said platform elements to saidstorage positions to lower said wheel-carrying means into engagement ofsaid wheels with the ground.

14. In a device of the kinddescribed, a plurality of elongated flatplatform elements, a supporting frame, means for pivotally mounting saidplatform elements at one end portion to said frame on vertically spacedhorizontal axes substantially parallel to the adjacent ends of saidplatform elements for movements between parallel horizontally disposedoperative positions in staired arrangement and generally verticallystorage positions overlying saidframe, a rigid support pivotallyconnected to the other end of each of said platform elements onvertically spaced horizontal axes parallel to the pivot axes at said oneend whereby said platform elements partake of simultaneous movementbetween said operative positive positions and said storage positions,said pivot axes being so arranged that said platform elements aredisposed in a common plane in said storage positions thereof, aplurality of wheels, wheel carrying means mounted on said frame formovements toward and away from engagement of said wheels with theground, and linkage operatively connected to one of said platformelements and to said wheel carrying means and responsive to movement ofsaid platform elements to their operative horizontal positions to movesaid wheel carrying means upwardly whereby said supporting frame restsupon the ground, said linkage being responsive to movement of saidplatform elements to said storage positions to lower saidpwheel carryingmeans into engagement of said wheels with the ground.

15. The structure defined in claim 14 in which said support comprisesleg structure movable between an operative supporting positionsubstantially normal to said platform elements in their horizontallydisposed positions andninoperative folded positions generally parallelto and lying against adjacentsurfacesfof said platform elements 13 intheir storage positions, whereby to limit swinging movements of saidplatform elements beyond said storage positions.

16. In a device of the kind described, a plurality of platforms normallyhorizontally disposed in staired arrangement, each of said platformscomprising a pair of elongated platform elements normally in alignedclosely spaced end to end relationship, -a supporting frame underlyingthe adjacent inner end portions of said platform elements, meanspivotally connecting the adjacent end portions of said platform elementsto said frame `on parallel horizontal axes extending substantiallyparallel to the inner ends of said platform elements, the axes ofpivotal connection of the platform elements of each platform beingvertically spaced from the pivot axes of other platform elements of astaired group thereof, whereby said platform elements are movablebetween their normally horizontal operative positions and generallyvertically disposed storage positions overlying said frame, a pair ofrigid leg structures each pivotally secured to the outer ends of theplatform elements of a different staired group thereof on verticallyspaced horizontal axes parallel to the pivot axes at the inner endportions of said platform elements and causing the elements of eaohstaired group thereof to move simultaneously between said horizontal andgenerally vertical positions, said leg structures being disposedgenerally normal to their respective platform elements when saidelements are in their horizontally disposed positions, said legstructure being disposed generally parallel to and engaging adjacentsurface portions of their respective platform elements in the generallyvertical storage positions thereof, a plurality of wheels, a pair ofwheel-carrying members one each underlying a different staired group ofsaid platform elements when in their horizontal positions and eachmounted on said frame structure for independent movements toward andaway from engagement of their respective wheels with the ground, andlinkage operatively connected to said staired groups of platformelements and to underlying ones of said wheel-carrying members andresponsive to movement of their respective groups of platform elementsto their normally horizontal positions to move their respectivewheel-carrying members upwardly whereby the frame structure rests uponthe ground, said linkage being responsive to movement of said groups ofplatform elements to said storage positions to lower their respectivewheel-carrying members into engagement of the wheels thereof with theground and elevate said frame from engagement with the ground.

17. rPhe structure defined in claim 16 in which said linkage comprises apair of rigid links, each pivotally connected at its upper end to theinner end portion of one of the platform elements of a different stairedgroup thereof on a horizontal axis in generally downwardly spacedparallel relation to the pivot axis of its respective platform element,the lower end of each link being pivotally secured to an underlying oneof said wheel carrying members on an axis parallel to the axis ofpivotal connection of the upper end of each link to its respectiveplatform element.

No references cited.

